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NUREG 0933
Displaying 26 - 48 of 48
DESCRIPTION Historical Background During the period 1978 to 1980, there were reports of fatigue failure of thermal sleeve assemblies in the piping systems of both PWRs and BWRs. The BWR problem was addressed by GE in NEDO-21821 and was resolved with a …
1
DESCRIPTION Historical Background STS for newer OLs require licensees to keep account of the number of transient occurrences to ensure that transient limits, based on design assumptions, are not exceeded. However, a number of older plants for which …
1
DESCRIPTION Historical Background On March 18, 1983, B&W expressed [1] concern for unanalyzed reactor vessel thermal stress that could occur during natural convection cooldown of PWRs. The concern emerged from a preliminary B&W evaluation of a voiding …
1
DESCRIPTION Historical Background This issue was identified by the ACRS in 1978 during the operating license reviews of some BWRs. The ACRS posed questions concerning the likelihood and effects of a LOCA which could cause interactions with the CRD …
1
DESCRIPTION This issue was raised by the ACRS in a memorandum [1] to the Commission in October 1983. Following the TMI-2 accident, the purpose and use of PORVs had been the subject of considerable analyses and discussion. The original purpose for which …
1
DESCRIPTION Historical Background In March 1982, leaks were detected in the heat-affected zones of the safe-end-to-pipe welds in two of the 28 in. diameter recirculation loop safe ends at Nine Mile Point Unit 1. Subsequent UT revealed extensive cracking …
1
DESCRIPTION Historical Background Low temperature overpressurization originally identified in NUREG 0371 [1] as item A-26. This issue later became USI A-26 and was resolved in September 1978 with a revision to SRP [2] Section 5.2. The resolution of USI …
1
DESCRIPTION Historical Background This issue was identified during the staff review of the Indian Point 2 and Zion PRAs [1] ; in both of these studies, the dominant interfacing systems LOCA events were estimated to be through the RHR suction valves. The …
1
DESCRIPTION In the prioritization of Issue 22, "Inadvertent Boron Dilution," it was found that inadvertent boron dilution events during cold shutdown operation do not constitute a significant risk to the public. Further work by DSI confirmed this …
1
DESCRIPTION Historical Background Potential stress corrosion cracking (SCC) of reactor vessel (RV) closure studs was raised as a GSI in December 1984. [1] Concerns were expressed that two contributors to SCC had not been subject to careful research and …
1
DESCRIPTION In an August 1983 memorandum, [1] the EDO requested a comprehensive review of NRC requirements in the area of nuclear power plant piping. In response to this request, the NRC Piping Review Committee (PRC) was formed to review and evaluate …
1
DESCRIPTION In December 1984, the staff recommended in SECY-83-357B [1] that rulemaking with regard to H 2 control for LWRs with large, dry containments could be safely deferred due to the greater inherent capability of these containments to accommodate …
1
DESCRIPTION Historical Background Potential seismic interaction involving the movable in-core flux mapping systems was identified as a generic issue in August 1985. [1] This potential interaction exists because portions of the in-core flux mapping system, …
1
DESCRIPTION Historical Background This issue was identified by NRR/EIB in February 1986 when it was suggested that Issue 106, "Piping and the Use of Highly Combustible Gases in Vital Areas," be expanded to include new safety concerns associated with the …
1
DESCRIPTION Historical Background This issue was raised in SECY-89-170 [1] and addressed the potential for control system vulnerabilities as a result of fire-induced alternate shutdown/control room panel interactions. Concern for these interactions arose …
1
DESCRIPTION Historical Background This issue was raised in SECY-89-170 [1] and addressed the effectiveness of manual fire-fighting in the presence of smoke. This concern arose as a result of an NRC-sponsored Fire Risk Scoping Study [2] which focused on …
1
DESCRIPTION Historical Background This issue was raised in SECY-89-170 [1] and addressed the effect of premature failure of fire barriers on CDF. Concern for fire barriers arose as a result of an NRC-sponsored Fire Risk Scoping Study [2] which focused on …
1
DESCRIPTION To calculate the value of RT PTS as required in 10 CFR 50.61 and 10 CFR 50, Appendix G, licensees must determine the value of the fast neutron fluence on the inside surface of their pressure vessels. Through a number of reviews, NRR found [1] …
1
DESCRIPTION The issue of fatigue of metal components was identified in SECY-93-049 [1] following the staff's senior management review of key license renewal issues. The recommendation to treat fatigue of metal components as a generic safety issue was …
1
In resolving GSIs over the years, the staff generally found it necessary to make assumptions and establish limitations on the scope of the issues. As a result of its review of the resolution of some GSIs, the ACRS expressed concerns that the assumptions …
1
DESCRIPTION In February 1993, The U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Reactor Regulation (NRR) completed a reassessment of the reactor fire protection review and inspection programs, in response to programmatic concerns raised …
1
DESCRIPTION The risk of failure from fatigue of various reactor coolant system components was studied under Issue 78 and later integrated into the NRR Fatigue Action Plan which was completed and documented in SECY-95-245. [1] The staff concluded that the …
1
DESCRIPTION Historical Background This issue was initiated [1] in response to a recommendation in the screening analysis of Generic Issue (A) I-195, "Potential Hydrogen Combustion in BWR Piping." GI-195 investigated the potential safety …
1
Page Last Reviewed/Updated 3/1/2026
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